Oil dispersants used in Gulf of Mexico spill causing alarm

A U.S. Air Force C-130 crew conducts a spray mission from Stennis International Airport, Kiln, MS in support of Deep Water Horizon. (Still shot from a video by Staff Sgt. Jose Contreras.)BP has used almost 600,000 gallons of the oil dispersant Corexit at the surface of the Gulf of Mexico to break-up the slick from the Deepwater Horizon spill, but concerns are growing about the environmental impact of those chemicals on the Gulf ecosystems and human residents of the area.

"There are a diversity of types of habitats in the Gulf," Lubchenco said. "Many of them are very important in support of a variety of wildlife and fisheries. At this point many of them are at risk of being affected but we don’t have any direct way to know exactly which ones or in what amount."

The exact chemical composition of the dispersants being used is
not public information, but the products are called Corexit 9527 and Corexit 9500. Corexit 9527 was used in the cleanup of the Exxon Valdez spill, and contains 2-butoxyethanol, a chemical solvent that is used in paint thinners and varnish removers, among other products.

The Agency for Toxic Substances and Disease Registry, a branch of the CDC, describes 2-butoxyethanol as a toxic compound with a host of negative effects on humans, including kidney and liver damage at high doses. The data material safety sheets for both Corexit 9527 and Corexit 9500 advise "Do not contaminate surface water," under the heading "Environmental Precautions."

Corexit 9500 is a newer formula that does not include 2-butoxyethanol. Jackson said the EPA had approved both Corexit products for use, and did not know how much of the total 582,416 gallons used was 9527 and how much was 9500.

Quinlan also reports that Nalco, the company that makes Corexit, "boasts oil-industry insiders on its board of directors and among its
executives, including an 11-year board member at BP and a top Exxon
executive."